Lubricants containing amino and hydroxy-substituted polyphenylthioethers

ABSTRACT

Lubricants are stabilized against oxidation and have their EP and detergency properties improved by adding thereto a property improving amount of an amino-substituted polyphenylthioether.

United States Patent [191 Nnadi [111 3 ,844,956 [451 Oct. 29, 1974 1 1LUBRICANTS CONTAINING AMINO AND IlYDROXY-SUBSTITUTEDPOLYPHENYLTHIOETHERS [75] lnventor: John C.'Nnadi,Glassboro,N.J.'

[73] Assignee: Mobil Oil Corporation, New York,

[221 Filed: Jan. 26, 1973 211 Appl. No.: 326,936

US. Cl 252/47.5, 252/46.7, 252/47, 252/48.2, 252/48.4, 252/48.6,252/402, 260/571 [51] Int. Cl C10m 1/42 [58] Field of Search 252/47.5,402

[56] References Cited UNITED STATES PATENTS 2,345,239 3/1944 Cook et a1.252/47.5 X

3,145,177 8/1964 Orloff et al. 252/52 3,156,728 11/1964 3,285,85411/1966 3,368,975 2/1968 Davis et al. 252/565 Primary ExaminerW. Cannon.

Assistant Examiner W. Cannon Attorney, Agent, or FirmAndrew L.Gaboriault; Raymond W. Barclay; Claude E. Setliff [5 7 ABSTRACT 13Claims, No Drawings I LUBRICANTS CONTAINING AMINO ANDHYDROXY-SUBSTITUTED POLYPI-IENYLTHIOETI'IERS BACKGROUND OF THEINVENTION 1. Field of the Invention The invention relates to improvedlubricant compositions. More particularly, it relates to lubricantswhich have been improved by the addition thereto of an amino andhydroxy-substituted polyphenylthioether.

2. Discussion of the Prior Art It is well known that many organicliquids and solid used in industrial fluids, such as oils and greases,.power transmission fluids and the like, may deteriorate and lose theirability to function when subjected to oxidation. Since these substancesare very often used at high temperatures, the rate of oxidativebreakdown can be very rapid. This problem is particularly important inthe operation of present day automotive and aircraft engines.

The breakdown of lubricant is almost always accompanied by the formationof sludge, corrosive acids and other products. These can harm the metalsurfaces of engines or other machines and interfere with efficientoperation of the lubricant.

The ideal way to deal with the problem of oxidation, of course, is toprevent it altogether. Since, however, most additives do not stopoxidation and the formation of potentially harmful solids, much work hasalso been done to find other materials that can keep the solids fromsettling on metal surfaces. Usually, therefore, it' is necessary to usea combination of additives where oxidation is not entirely stopped onefor retarding oxidation. the other for keeping in suspension thosesolids resulting from the oxidation that does occur. The art does notexpect to find single additives that on the one hand retard oxidationand on the other act as dispensing agents.

No art is known which discloses the compounds disclosed herein asantioxidants or dispersants in lubricants. There is patent art, however,which discloses analogous compounds as lubricants. One of these is U.S.Pat. No. 3,490,737, which teaches a combination of functional fluid andmetallic compound. Another is U.S. Pat. No. 3,538,l66, disclosing aprocess for making an analogous thioether which may be used as afunctional fluid.

SUMMARY OF THE INVENTION In accordance with the invention, there isprovided a lubricant composition comprising a major proportion of alubricant and an antioxidant or dispersant amount of a compound of theformula wherein R and R are hydrogen, hydrocarbyl of from I 6 to I00carbon atoms, preferably alkyl having from 1 to I00 carbon atoms,preferably from about 4.to 20 carphoric acids and derivatives thereof,mercapto,

halogeno hydroxyl and cyano. For solubility in oil R, R should havegreater than two carbon atoms, preferably 4 or more. X and Y arehydroxyl or amino and n is from I to l0. The X's and Ys and Rs and R smay be the same or different. The product may also be a mixture,

i.e., where it may vary. The most usual mixture will comprise compoundsin which n is l, 2, or 3.

DESCRIPTION OF SPECIFIC EMBODIMENTS In general, the polyphenylthioethersmay be prepared in known ways. One method, the method used herein,involves reactions that may be set forth as follows:

Q'and M are the equivalents of reactants, varied to give the desiredpolymeric product. For example the tetramer is obtained when Q is 4 andM is 3.

The amino group may be protected by other reactions such as acetylationor by neutralization with other mineral acids such as HBr, HF, H 50 or HPO or with organic acids such as carboxylic or sulfonic acids. Thepolymers may then be copolymerized with a phenol and SCI to yieldpolymers having X as NH: and OH. In a variation of the procedure toobtain polymers containing both the NH and OH groups, mixtures of phenoland aniline with the protectedNH- group or of partially Sch-polymerizedphenol and aniline with protected NH group may be reacted. Suitableproducts may be obtained with partially blocked or totally unblockedarylamines as starting materials.

vent for the process. Some of these are, forexample tetrahydrofuran andparaffims.

The reaction temperature can range from 0C to 5 300C with the rangebetween 0 and 180C preferred.

The amine hydrochloride portion of the product can be reconverted to theparent amine by washing the product with aqueous solutions of sodium orpotassium hydroxides and carbonates or those of calcium. zinc. magnesiumand barium. This may also be done by stirring the product with excessamounts of secondary and tertiary alkylamines.

The starting aryl compound for the polymers of this invention are thoseof the formula examples of which appear as follows:

The additives of this invention can be used in a wide variety oflubricant media. They can be used as effective agents in lubricatingoils such as mineral oils, both naphthenic and paraffinic. includingthose containing substantial amounts of aromatic oils, synthetic oils,such as synthetic hydrocarbons obtained by polymerizing olefins.synthetic esters and polysiloxanes and the like. The term lubricant alsoincludes greases made by adding a grease forming agent to any of thoseoils mentioned. but is not meant to include any of the thioethersthemselves as lubricants. The thioethers disclosed herein are especiallyuseful in stabilizing a lubricating oil made by reacting an aliphaticmonocarboxylic acid containing from 4 to [0, preferably 5 to 9. carbonatoms with pentaerythritol. including monoand dipenterythritol ormixtures thereof. A widely used lubricating oil is made frommonopentaerythritol and a mixed C -,C acid. preferably C,-, and C Forpurposes of illustration. the following examples are offered. It is tobe remembered they are for illustration only and are not intended tolimit the scope of the invention. Parts are by weight.

Example 1 NH: NH: NH:

nHzs Jz X1125 kept at I50C for 4 hours under nitrogen purge. Thereaction was cooled. mixed with 500 cc of toluene and cc oftetrahydrofuran and then washed once with l00 cc 10 percent NaOHsolution and twice with 250 cc of H 0. The washed product was distilledto remove the solvents and unreacted dodecylaniline. The final stage ofdistillation was carried out to a pot temperature of 180C and 3 mm Hg,where it was held for 2 hours. The yield of product was 509 g. itcontained 2.7 percent N and 2.94 percent S and had a total base numberof 8 I. This product consisted mostly of trimer, tetramer and pentamer.

Example 2 i 7 '7 NI-Is MHVNHZ Example3 ii; ET-[ ina m I S O S l CiHo L4H0 J2 (Hr From l50 g (l mole) of p-n butylaniline, 35.5 g of HCI (1mole) and 76.5 g of SCl (0.75 mole) reacted in 400 cc tetrahydrofuransolvent as described in Example 1. I32 g of product was obtained. Itcontained 5.36 percent N and 8.94 percent S, and had a molecular weight(by vapor pressure lowering) of 649, indicating the tetramer.

Example 4 Niii on on Nil:

lo s ol nHzs Collin nHiu "Has One mole (220 g) of nonyphenol wasdissolved in 300 cc of tetrahydrofuran and reacted with 50 g of SCI(about 0.5 mole) at 35*50C. The reaction mixture was slowly raised to Cby distilling off some tetrahydrofuran and kept at l50-l60C undernitrogen purge for 4 hours after which it was cooled to roomtemperature. To this product was added 300 g of dodecylanilinehydrochloride dissolved in 300 cc of tetrahydrofuran. Then 101 g SCI wasadded and the reaction carried out as described in Example 1. The yieldof product after holding at 180C 3 mm Hg for 2 hours was 452 g. Toreconvert it to the aniline, the product was dissolved in 200 cc tolueneand stirred with about 1 l g of triethylamine and filtered. Finally thereaction mixture was again distilled by raising the temperature to andheld it at 180C at 3 mm Hg for 2 hours. The yield of product was 476 g.

EVALUATION OF PRODUCTS The antioxidant properties of the novel compoundsof this invention are measured by adding these compounds to a suitableoil and subjecting the oil to oxidation at high temperatures. The testis a bulk oil catalytic oxidation process in which a stream of dry airis passed through a heated sample of the lubricant compositions for atime at various elevated temperatures in the presence of iron, copper,aluminum and lead as catalysts. The metal samples consist of 15.6 sq.in. of sandblasted iron wire, 0.78 sq. in. of polished copper wire, 0.87sq. in. of polished aluminum wire, and 0.167 sq. in. of polished leadsurface. The antioxidant activity is evaluated as the ability of theadditive to control the acid number and viscosity of the oil and'preventthem from rising at an unduly rapid rate. The sludge formation duringthe oxidation is estimated visually. The base stock is a mixed ester ofpentaerythritol prepared by reacting an acid mixture of l mole ofpelargonic acid and 3 moles of commercial valeric acid with 1 mole oftechnical grade pentaerythritol or a mineral oil.

The results of this test are tabulated below in separate tables.

OXIDATION TEST IN MIXED ESTER FLUID The thioethers disclosed'herein weretested as detergentsby the Sulfuric Acid Neutralization Test and thePyruvic Acid Dispersion Test. The Sulfuric Acid Neutralization Testgives a measure of the ability of detergent additives to neutralizestrong acids formed in engines operating on sulfur containing fuels. H50 is mixed with a heated blend of the additive and the oil. A solutionof this is formed in isooctane which is then centrifuged to separateinsolubles.

0 The optical density of the clear solution is then measured. From thisvalue the optical density of the original additive blend diluted to acorresponding amount with isooctane is subtracted. The difference givesthe optical density of the dispersed H 50 reaction prodisooctane-oilsolution is then determined. The average optical density of theoil-isooctane solution is expressed as the optical density of thedispersed H 50, reaction product. The average density of the acetonesolution is expressed as the optical density of the values or either onealone is used in the evaluation of detergent additives.

The Pyruvic Acid Dispersion Test gives a measure of the dispersant valueof additives and serves to predict the performance of detergentadditives in engines operating on low sulfur content fuels. When used incombination with the neutralization of H 80 bench test procedures itserves to predict the performance of detergentadditives in enginesoperating on high sulfur content fuels. Pyruvic acid is mixed with aheated blend of the additive and the oil. The mixture is diluted withbenzene' and centrifuged to separate insolubles. The insolublesaredissolvedinacetone. The optical density of the oil-benzene solutiongives the total amount of color. From this value the optical density ofthe initial additive blend diluted with benzene to a correspondingamount is subtraced. This corrected value is expressed as the opticaldensity of the dispersed pyruvic acid polymer. The optical density ofthe acetone solution is (24 hour oxitlati in) wt, expressed as theoptlcal denslty of'the non dispersed lnhihiwr n- NN Sludge pyruvic acidpolymer. These values are used in evalua- N .m s as N tion of thedetergent additives. 450 14.25 5245 Trace The table below'summarizes theresults of the tests twmvlv I run. The higher thepercentage of the testrun with py- 5 I1 Ni] ruvic acid, the better the additive, while a lowervalue 57 N" in the sulfuric acid test indicates a-better additive. I\nlllplc 2 0.5 425 L65 25 Light 450 2.85 60 Light 1.0 425 0.76 2l Tracewt sulfuric Pyruvic 450 2.25 N1 Fwmplc .l 0.5 425 1.6 22 Li ht 50 4502.x so Light 1.0 425 0.7 12 Trace Nflflc (L098 5 450 2.2 50 Nil Example1 3 0.024 97.3 Iimmplc 4 0.5 425 4.05 170 Nil Example 2 3 0.137 81.9 1.0425 -1.05 114 Nil Example 4 1 0.144 86.5

OXIDATION TEST IN MINERAL 01L* Wt. Oxidation Inhibitor I Temp.. F Time,hrs. NN KV. Sludge None 325 40 l7.() 334 Heavy 325 72 24.3 Trace ExampleI 2 325 72 L35 8 Nil 4 325 72 1.65 13 Light 4 325 40 L35 8 Trace Example4 5 325 72 3.9 2| Nil sec Snlvunt refined paraffinic neutral.

acts. The optical density of an acetone extraction of the v Testsindicated that the thioethers of this invention are also useful as EPagents. The product of Example I was placed in a mixed bright andneutral mineral oil stock (62 and 38 percent by volume, respectively)having a viscosity of 481 SUS at lOF and 63 SUS at 210F. The test wasrun in the well known Shell Four- Ball Test at a 60 kg load at lO0F. for30 minutes. with the following results:

Concentration Wear Scar Diameter (mm) Wt. "/1 500 rpm 1000 rpm In usingthe thioethers of the invention as antioxidants. dispersants or EPagents. the concentration may be selected from the range of from about0.00] to about percent by weight, preferably from about I to about 5percent.

I claim:

1. A lubricating oil or grease composition comprising a major proportionof said lubricating oil or grease and an antioxidant or dispersantamount of a compound of wherein R and R are hydrogen or hydrocarbylcontain- Ill ing from 1 to I00 carbon atoms, X and Y are selected fromthe group consisting of amino and hydroxy, such that said X and Y arenever all amino or all hydroxy, and n is from zero to 10, or mixtures ofsuch compounds.

2. The composition of claim i wherein the compound is present in therange of from about 0.001 to about 20 percent by weight.

3. The composition of claim 1 wherein the lubricant is a lubricatingoil.

4. The composition of claim I wherein the lubricant comprises a grease.

5. The composition of claim 3 wherein the lubricating oil is a minerallubricating oil.

6. The composition of claim 3 wherein the lubricating oil is a syntheticlubricating oil.

7. The composition of claim 6 wherein the synthetic lubricating oil isan ester of an aliphatic monocarboxylic acid of from 4 to l0 carbonatoms, and mixtures thereof, and pentaerythritol.

8. The composition of claim 7 wherein the acid is a mixture ofpelargonic and valeric acids.

9. The composition of claim 1 wherein R and R are dodecyl, X is NH, andn is 2.

10. The composition of claim 1 wherein R and R are dodecyl, X is NH andn is zero.

11. The composition of claim 1 wherein R is dodecyl, R is nonyl, X is NHY is OH and n is 2.

12. The composition of claim 1 wherein the hydrocarbyl is alkyl havingfrom I to carbon atoms, aryl having from 6 to 100 carbon atoms andaralkyl having from 7 to 100 carbon atoms.

13. The composition of claim 12 wherein the alkyl contains from 4 to 20carbon atoms.

1. A LUBRICATING OIL OR GRASE COMPOSITION COMPRISING A MAJOR PROPORTIONOF SAID LUBRICATING OIL OR GRASES AND AN ANTIOXIDANT OR DISPERSANTAMOUNT OF A COMPOUND OF THE FORMULA
 2. The composition of claim 1wherein the compound is present in the range of from about 0.001 toabout 20 percent by weight.
 3. The composition of claim 1 wherein thelubricant is a lubricating oil.
 4. The composition of claim 1 whereinthe lubricant comprises a grease.
 5. The composition of claim 3 whereinthe lubricating oil is a mineral lubricating oil.
 6. The composition ofclaim 3 wherein the lubricating oil is a synthetic lubricating oil. 7.The composition of claim 6 wherein the synthetic lubricating oil is anester of an aliphatic monocarboxylic acid of from 4 to 10 carbon atoms,and mixtures thereof, and pentaerythritol.
 8. The composition of claim 7wherein the acid is a mixture of pelargonic and valeric acids.
 9. Thecomposition of claim 1 wherein R and R'' are dodecyl, X is NH2 and n is2.
 10. The composition of claim 1 wherein R and R'' are dodecyl, X isNH2 and n is zero.
 11. The composition of claim 1 wherein R is dodecyl,R'' is nonyl, X is NH2, Y is OH and n is
 2. 12. The composition of claim1 wherein the hydrocarbyl is alkyl having from 1 to 100 carbon atoms,aryl having from 6 to 100 carbon atoms and aralkyl having from 7 to 100carbon atoms.
 13. The composition of claim 12 wherein the alkyl containsfrom 4 to 20 carbon atoms.